During the spinning process, spinning machines (for example a rotor or air jet machine) will often stop during yarn production, either intentionally or unintentionally. The yarn end that arises out of these production stops (for example because of a quality cut or a yarn break), will be wound onto the still-rotating bobbin of a winding device. For the purposes of the piecing process, the yarn end located on the bobbin must be released from the bobbin surface, for example with the aid of a suitable suction device, in order to be able to feed the yarn end in the actual spinning direction back towards the spinning station. Furthermore, as a rule, a defined section of the yarn must be removed prior to the piecing process, as the existing yarn end is usually not suitable. As a result, a significant delay occurs in continuing the spinning process, in particular because the locating of the yarn and the subsequent removal of the end section is primarily carried out by a service robot, which has to be driven to the respective spinning station.
It is an object of the present invention to propose a spinning machine, as well as a process for removing a yarn end section in a spinning machine prior to a subsequent piecing process, wherein with the aid of the present invention, the piecing time is reduced in comparison to prior art. Additional objects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
According to the present invention, the spinning station includes a yarn end disposal means, which is at least partly arranged between the outlet station of the spinning device (including for example a spinning nozzle or a spinning rotor) and the winding device, and with the aid of which the end section of the produced yarn is able to be cut from the rest of the yarn and eliminated. The removal of the yarn section not suitable for the piecing device can thus be carried out directly at the spinning station, namely prior to the arrival of a service robot or or service personal at the respective spinning station.
If an interruption in the spinning process occurs, for example in the context of a quality cut (which is intentionally carried out when one or a number of the monitored yarn parameters do not correspond to the nominal values), or an unplanned yarn break, preparations for the yarn for the subsequent piecing process can begin directly after the interruption. While it is usually necessary after a yarn break to release the yarn end from the bobbin surface and subsequently feed it to the yarn end disposal means (for example by means of a separate gripping device), the design of the spinning station according to an embodiment of the present invention opens up enormous advantages, in particular for the execution of the quality cut. It is in principal possible to slow down the production of yarn subsequent to the detection of a deviation from a previously defined yarn parameter. In this case, it is conceivable to gradually reduce the transport speed of the delivery device, the winding arrangement and if present, the withdrawal device, with which the yarn is withdrawn from the spinning device. Subsequent to a predetermined reduction of the respective transport speeds, an interruption of the yarn production occurs, as the feed speeds fall below the minimal values which should be maintained for yarn production. The term quality cut does not therefore essentially imply a cutting process. Rathermore, an interruption of the spinning process is implied, which is introduced because of irregularities of defined yarn parameters.
If, then, the passing of the yarn end at a certain point (for example at the outlet station of the spinning device) is detected by, for example, a monitoring unit arranged outside of the spinning device, the above-mentioned units (feed device, winding device, withdrawal device) can be completely stopped. The yarn end is now located at a defined position and, if required, can be affixed accordingly, for example with the aid of a roller pair of the withdrawal device. If the yarn end is fixed in the area of the yarn end disposal means according to aspects of the present invention, the yarn end can be reliably gripped by the yarn end disposal means without any further handling devices being necessary. Subsequent thereto, the end section of the yarn which does not meet the specifications is wound on by the winding device, wherein in the case of a slowing down of the feed speeds, the end section should advantageously correspond to the end section which was produced at the start of the slow-down. The wound-on end section can, for example, be wound on or suctioned by the yarn end disposal means and then cut off and accordingly eliminated (for example in the area of a central collecting area).
When the service robot approaches the area of the spinning station, a suitably prepared yarn end is already present, which can be fixed at a predetermined station, advantageously in the area of an outlet of the yarn end disposal means. Consequently, the robot does not have to search for the yarn end on the surface of the winding device and to unwind it, as is the case in prior art. The time-consuming removal by the robot of the above mentioned end section of yarn, which is no longer suitable for the piecing process, is also omitted. As a result, the time required by the robot for the piecing process is significantly reduced.
Furthermore, it is advantageous when the yarn end disposal means includes a suction channel, by means of which the end section of the yarn is able to be sucked in and/or the cut off end section is able to be eliminated. The suction channel can be connected to a central vacuum source of the spinning machine. It is of course also conceivable to equip the suction channel with its own vacuum source, for example a Venturi nozzle, which is only then put into operation when a yarn end section has to be removed at the respective spinning station.
It is particularly advantageous when the yarn end disposal means includes a cutting unit, with the aid of which the end section to be removed is able to be separated from the rest of the yarn. In particular, when the cutting unit is integrated in the above mentioned suction channel, the result is a compact unit, with the aid of which the end section to be removed is not only able to be separated but also removed, that is, disposed of. The cutting unit can, when required, be brought into the proximity of the end section of the yarn and/or be activated or deactivated.
Alternatively, it is of course understood that it is possible to apply the yarn-cutting device of a yarn-monitoring unit (“clearer”), which if required, can also be designed as a cutting unit. The yarn-cutting device is, in this case, advantageously positioned between the suction channel of the yarn end disposal means and the withdrawal device, and monitors predetermined characteristics and the presence of produced yarn in the area of the yarn-monitoring unit. A separate cutting device within the suction channel could be omitted in this embodiment.
It is also advantageous when the spinning station comprises a withdrawal device, formed for example by a withdrawal roller pair, for the withdrawal of the yarn out of the spinning device, wherein the yarn end disposal means is arranged between the spinning device outlet and the withdrawal device. As already implemented, it is in principal possible to selectively slow down the spinning station for carrying out a so-called quality cut until the feed speed, in particularly that of the feed device, slows down to such an extent that an interruption of the yarn production occurs. The yarn end which occurs as a result can, if required, be fixed between the roller of the withdrawal device, wherein the fixing, that is the associated halt of the withdrawal rollers, can be initiated by a sensor, which monitors the presence of a yarn at a defined station downstream of the outlet of the spinning device.
The withdrawal rollers release the yarn end again, before the yarn end is gripped by the yarn lead-away and is, for example, sucked into the suction channel (under the action of a corresponding reverse rotation of the bobbin supported in the winding device.) Alternatively, it is also possible to fix the yarn constantly between the withdrawal rollers, wherein the withdrawal rollers also execute a reverse turn according to the rotational direction of the winding device (that is, a reverse turn in the opposite rotational direction to that during the actual spinning process), as long as the end section of the yarn is wound off the winding device. The advantage herein lies in the fact that the yarn end is also still fixed by means of the withdrawal device at a defined station when the end section of the yarn is separated from the yarn end disposal means and removed. The robot, which arrives if required, can selectively grip the yarn end prior to the actual piecing process, so that the time loss caused by searching for the yarn end is avoided.
There are particular advantages when the winding device and/or (each) withdrawal device comprises a reversibly drivable drive unit. Even if it were sufficient to equip the mentioned units with a free running device for the winding off of the yarn section to be removed, it is advantageous when an active drive against the transport direction prevailing during the spinning process is possible. In this way, a controlled winding off of the end section of the yarn is possible, wherein a non-defined after-running of the respective bobbin can be avoided.
There are also advantages when the spinning machine comprises a number of adjacently arranged spinning stations, wherein each spinning station includes a separate yarn end disposal means. The spinning stations are independent of one another, so that at each spinning station where a piecing process is to take place, the respective end section of the yarn, which is unsuitable for piecing, can be removed.
It is particularly advantageous when the suction channel of the yarn end disposal means is connected to a suction device of the feed device. Suction devices of this type are usually present in the area of the drafting unit of an air jet spinning machine which forms the feed device, or of an opening roller of a rotor spinning machine, the suction devices serving to eliminate lint, dust and other impurities. If the suction channel is coupled with a suction device of this type, a separate suction device can be omitted. The connection between the suction channel and the suction device of the feed device can for example be made by means of pipe fittings and/or a flow diverter.
It is also advantageous when a valve and/or a flow diverter is assigned to the suction channel, with the aid of which the air pressure inside the suction channel is able to be regulated. The suction channel can be coupled with a central suction installation. Depending on whether or not it is necessary for the end section of yarn unsuitable for piecing to be removed at the respective spinning station or not, the suction channel is subject to low pressure, or respectively, an airstream which effects a sucking-in of the yarn end. The valve, or respectively, the flow diverter is advantageously controlled with the aid of a suitable controlling device, which in turn can, for example, be connected to a yarn sensor.
It is most advantageous when the winding device includes a yarn-traversing device, wherein a yarn-lifting device is assigned to the yarn-traversing device, with the aid of which yarn-lifting device the yarn is able to be brought out of the effective range of the yarn-traversing device. By lifting the yarn, breaking of the yarn or damage to the traversing device is prevented during the winding process of the yarn end section from the winding device, as yarn and traversing device no longer come into contact during this phase.
It is also advantageous when the yarn-lifting device includes a lifting element that is movable in relation to the yarn, the lifting element being advantageously aided by a pneumatic cylinder. The yarn runs via the lifting element and can no longer come into contact with the traversing element of the traversing device. At the latest when the piecing process is completed, the yarn-lifting device or respectively, the pneumatic cylinder, returns to its starting position, in which the traversing element effects a traversing motion of the yarn while the yarn is being wound off the winding device.
It is in addition advantageous when the lifting element extends at least over the width of the winding device. This ensures that the yarn is reliably gripped by the lifting element when the lifting element is activated. A movement of the lifting element in the width direction of the winding device (that is in axial direction of a placed bobbin) is therefore not necessary. The lifting device can herein for example be rod-shaped and connected to a respective driving element, for example the above-mentioned pneumatic cylinder.
Alternatively it is self-evident that provision can be made for the applied yarn-traversing device to comprise one or more traversing elements (for example in the form of a yarn guide), which, if required, are movable, swivel-mounted or otherwise movable in such a way that they are able to be placed in a position in which they do not come into contact with the yarn during the winding off of yarn (from the winding device). For example, it is conceivable that in this connection a so-called flyer traversing device could be applied. A flyer traversing device typically includes two or more counter-rotatable flyer elements, which alternately come into contact with the yarn to be wound on and move the yarn to and fro accordingly during winding on. In order to prevent the traversing element from coming into contact with the yarn during the winding off process (this could have a negative effect on the winding off process), it can be provided that the respective traversing elements are moved into a so-called winding off position. The winding off position is a position in which the traversing element, or respectively, the traversing elements, can no longer come into contact with the yarn which is running between the winding device and the withdrawal device. If the so-called flyer elements are applied, they would be rotated in a position in which the sections which come into contact with the yarn during winding off are located in an area, which during winding off are located outside of the yarn running path.
According to additional aspects of the present invention, the process for discharging an end section of a yarn in a spinning machine prior to a subsequent piecing process is characterized in that the end section of the yarn is wound off from the winding device subsequent to an interruption of the spinning process, and in that the end section is gripped with the aid of a component part of the spinning station in the form of a yarn end disposal means, then separated from the rest of the yarn and subsequently discharged from the area of the spinning station, wherein the yarn end disposal means is arranged at least partly between the outlet of the spinning device and the winding device. Each individual yarn can therefore be treated accordingly at each spinning station before a service robot or the relevant service personnel for carrying out the piecing process arrives. In addition, the yarn end is located at a defined place subsequent to the removal of the end section of the yarn unsuitable for the piecing process, namely advantageously in the area of the yarn end disposal means, and can if required (as mentioned above) be fixed thereto. The yarn end disposal means can be designed according to one or a number of the features described above, wherein this is not absolutely necessary.
It is advantageous in particular when the spinning station includes a withdrawal device for withdrawing the yarn from the spinning device, wherein the transport speeds of the delivery device, the withdrawal device, and the winding device can all be gradually reduced to a standstill prior to winding off the end section of the yarn. The reduction takes place advantageously in such a way that the end of the produced yarn is located between the outlet of the spinning station and the winding device, advantageously between the outlet of the spinning station and the withdrawal device, subsequent to the reduction. Advantageously, at least one section of the yarn end disposal means extends in this area (for example the suction channel). The yarn end resulting from the reduction of the delivery speeds is located in this case subsequent to the standstill of the above mentioned units at a defined place and can be gripped reliably by the yarn end disposal means, for example by means of suction. A backwards feed of the yarn, which is already wound onto the winding device, then takes place until the designated end section is taken up by the yarn end disposal means.
Subsequently, the end section is cut off and disposed of (for example via a suction installation of the spinning machine which is connected to the suction channel). If the yarn was gripped continuously by relevant withdrawal rollers of the withdrawal device, subsequent to the winding off of the yarn and during the removal of the end section of the yarn, the yarn generated by the removal of the yarn end section is thus located also in the area of the withdrawal device. This yarn end can now be selectively gripped by a service robot or by a member of the service personnel and fed to the subsequent piecing process.
It is also advantageous when the end section of the yarn to be removed is sucked up with the aid of a suction channel of the yarn end disposal means and is removed subsequent to separation from the rest of the yarn. Relevant suction channels are known from other parts of the spinning machine and can be subjected individually to low pressure by means of the relevant structural or computer-controlled measures.
It is particularly advantageous when a valve and/or a flow diverter is arranged to the suction channel and when, with the aid of the valve and/or the flow diverter, the air pressure can be regulated inside the suction channel. The prevailing air stream in the flow channel can therefore be individually adapted. An air current is advantageously only then generated when the yarn end section is to be removed. In the normal spinning process, the valve is closed, or the flow diverter is moved accordingly until an energy-consuming air current no longer prevails within the suction channel.
It is also advantageous when the spinning station comprises a withdrawal device for the withdrawal of the yarn from the spinning device, wherein the yarn end removal takes place between the outlet of the spinning device and the withdrawal device. The named area is usually easily accessible, so that a robot or a member of the service personnel can reliably grip the yarn end and fed to the piecing process, in which the yarn end is joined to the fibre material coming from the feeding device, prior to the continuation of the actual spinning process.
There are also advantages when the yarn is fixed with the aid of the yarn end disposal means and/or the withdrawal device, e.g. its withdrawal roller pair after the separation of the end section of the yarn, until it is taken over manually or with the aid of a service robot and fed to the piecing process. The search for the yarn end is omitted in this case, so that the time required for the piecing process can be further reduced.
There are also advantages when the end section of the yarn to be removed is wound off the bobbin of the winding device in that a bobbin drive is driven in the opposite direction to the winding on direction, which prevails during the spinning process. This results in a controlled winding off process, which can prevent looping formation or other undesirable reductions in yarn tension. In this case, for example, the bobbin can be driven directly. A drive via a winding roller, which is disposed on the surface of the bobbin and effects an indirect drive, is of course also possible.
It is also advantageous when the winding device includes a yarn-traversing device and a yarn lifting arrangement is assigned to the yarn-traversing device, wherein the yarn is removed from the effective area of the yarn-traversing device with the aid of the yarn raising arrangement at least during the winding off of the end section of the yarn to be removed. While during the process the traversing device provides that the produced yarn is deposited in the known way on the bobbin, contact between the traversing device and the yarn during the winding off process is undesirable in order to avoid damage to the yarn and/or the traversing device. This can be achieved in a simple way by means of the yarn-lifting device in such a way that the yarn in the area of the traversing device is moved only so far away as that no contact occurs with the traversing device.